如何在Android中使用SharedPreferences来存储,获取和编辑值

Question

我想存储一个时间值,需要检索和编辑它.我SharedPreferences该怎么用呢？

Answer 1

要获取共享首选项,请在您的活动中使用以下方法:

SharedPreferences prefs = this.getSharedPreferences(
      "com.example.app", Context.MODE_PRIVATE);

要阅读首选项:

String dateTimeKey = "com.example.app.datetime";

// use a default value using new Date()
long l = prefs.getLong(dateTimeKey, new Date().getTime()); 

编辑和保存首选项

Date dt = getSomeDate();
prefs.edit().putLong(dateTimeKey, dt.getTime()).apply();

android sdk的示例目录包含检索和存储共享首选项的示例.它位于:

<android-sdk-home>/samples/android-<platformversion>/ApiDemos directory

编辑==>

我注意到,重要的是在这里commit()和apply()这里写下区别.

commit()true如果值成功保存,则返回false.它同步将值保存到SharedPreferences .

apply()在2.3中添加,并且在成功或失败时不返回任何值.它会立即将值保存到SharedPreferences,但会启动异步提交.更多细节在这里.

Answer 2

要在共享首选项中存储值:

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("Name","Harneet");
editor.apply();

要从共享首选项中检索值:

SharedPreferences preferences = PreferenceManager.getDefaultSharedPreferences(this);
String name = preferences.getString("Name", "");
if(!name.equalsIgnoreCase(""))
{
    name = name + "  Sethi";  /* Edit the value here*/
}

Answer 3

要编辑从数据sharedpreference

 SharedPreferences.Editor editor = getPreferences(MODE_PRIVATE).edit();
 editor.putString("text", mSaved.getText().toString());
 editor.putInt("selection-start", mSaved.getSelectionStart());
 editor.putInt("selection-end", mSaved.getSelectionEnd());
 editor.apply();

为了获取从数据sharedpreference

SharedPreferences prefs = getPreferences(MODE_PRIVATE); 
String restoredText = prefs.getString("text", null);
if (restoredText != null) 
{
  //mSaved.setText(restoredText, TextView.BufferType.EDITABLE);
  int selectionStart = prefs.getInt("selection-start", -1);
  int selectionEnd = prefs.getInt("selection-end", -1);
  /*if (selectionStart != -1 && selectionEnd != -1)
  {
     mSaved.setSelection(selectionStart, selectionEnd);
  }*/
}

编辑

我从API Demo示例中获取了这个片段.那里有一个EditText盒子.在这context不是必需的.我正在评论相同的.

Answer 4

来写 :

SharedPreferences preferences = getSharedPreferences("AUTHENTICATION_FILE_NAME", Context.MODE_WORLD_WRITEABLE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("Authentication_Id",userid.getText().toString());
editor.putString("Authentication_Password",password.getText().toString());
editor.putString("Authentication_Status","true");
editor.apply();

阅读 :

SharedPreferences prfs = getSharedPreferences("AUTHENTICATION_FILE_NAME", Context.MODE_PRIVATE);
String Astatus = prfs.getString("Authentication_Status", "");

Answer 5

最简单的方法:

要保存:

getPreferences(MODE_PRIVATE).edit().putString("Name of variable",value).commit();

要检索:

your_variable = getPreferences(MODE_PRIVATE).getString("Name of variable",default value);

Answer 6

在偏好中设置值:

// MY_PREFS_NAME - a static String variable like: 
//public static final String MY_PREFS_NAME = "MyPrefsFile";
SharedPreferences.Editor editor = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE).edit();
 editor.putString("name", "Elena");
 editor.putInt("idName", 12);
 editor.commit();

从首选项中检索数据:

SharedPreferences prefs = getSharedPreferences(MY_PREFS_NAME, MODE_PRIVATE); 
String restoredText = prefs.getString("text", null);
if (restoredText != null) {
  String name = prefs.getString("name", "No name defined");//"No name defined" is the default value.
  int idName = prefs.getInt("idName", 0); //0 is the default value.
}

更多信息:

使用共享首选项

共享首选项

Answer 7

单身共享首选项类.它可能在将来对其他人有所帮助.

import android.app.Activity;
import android.content.Context;
import android.content.SharedPreferences;

public class SharedPref
{
    private static SharedPreferences mSharedPref;
    public static final String NAME = "NAME";
    public static final String AGE = "AGE";
    public static final String IS_SELECT = "IS_SELECT";

    private SharedPref()
    {

    }

    public static void init(Context context)
    {
        if(mSharedPref == null)
            mSharedPref = context.getSharedPreferences(context.getPackageName(), Activity.MODE_PRIVATE);
    }

    public static String read(String key, String defValue) {
        return mSharedPref.getString(key, defValue);
    }

    public static void write(String key, String value) {
        SharedPreferences.Editor prefsEditor = mSharedPref.edit();
        prefsEditor.putString(key, value);
        prefsEditor.commit();
    }

    public static boolean read(String key, boolean defValue) {
        return mSharedPref.getBoolean(key, defValue);
    }

    public static void write(String key, boolean value) {
        SharedPreferences.Editor prefsEditor = mSharedPref.edit();
        prefsEditor.putBoolean(key, value);
        prefsEditor.commit();
    }

    public static Integer read(String key, int defValue) {
        return mSharedPref.getInt(key, defValue);
    }

    public static void write(String key, Integer value) {
        SharedPreferences.Editor prefsEditor = mSharedPref.edit();
        prefsEditor.putInt(key, value).commit();
    }
}

只需在MainActivity上调用SharedPref.init()一次即可

SharedPref.init(getApplicationContext());

写数据

SharedPref.write(SharedPref.NAME, "XXXX");//save string in shared preference.
SharedPref.write(SharedPref.AGE, 25);//save int in shared preference.
SharedPref.write(SharedPref.IS_SELECT, true);//save boolean in shared preference.

阅读数据

String name = SharedPref.read(SharedPref.NAME, null);//read string in shared preference.
int age = SharedPref.read(SharedPref.AGE, 0);//read int in shared preference.
boolean isSelect = SharedPref.read(SharedPref.IS_SELECT, false);//read boolean in shared preference.

Answer 8

存储信息

SharedPreferences preferences = getSharedPreferences(PREFS_NAME,Context.MODE_PRIVATE);
SharedPreferences.Editor editor = preferences.edit();
editor.putString("username", username.getText().toString());
editor.putString("password", password.getText().toString());
editor.putString("logged", "logged");
editor.commit();

重置您的偏好

SharedPreferences.Editor editor = preferences.edit();
editor.clear();
editor.commit();

Answer 9

在任何应用程序中,都可以通过PreferenceManager实例及其相关方法访问默认首选项getDefaultSharedPreferences(Context).

使用SharedPreference实例,可以使用getInt(String key,int defVal)检索任何首选项的int值.我们对这种情况感兴趣的偏好是反制的.

在我们的例子中,我们可以SharedPreference使用edit()修改我们案例中的实例,并使用putInt(String key, int newVal)我们增加应用程序的计数,该应用程序超出应用程序并且相应地显示.

要进一步演示此操作,重新启动并重新启动应用程序,您会注意到每次重新启动应用程序时计数都会增加.

PreferencesDemo.java

码:

package org.example.preferences;
import android.app.Activity;
import android.content.SharedPreferences;
import android.os.Bundle;
import android.preference.PreferenceManager;
import android.widget.TextView;

public class PreferencesDemo extends Activity {
   /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        // Get the app's shared preferences
        SharedPreferences app_preferences = 
        PreferenceManager.getDefaultSharedPreferences(this);

        // Get the value for the run counter
        int counter = app_preferences.getInt("counter", 0);

        // Update the TextView
        TextView text = (TextView) findViewById(R.id.text);
        text.setText("This app has been started " + counter + " times.");

        // Increment the counter
        SharedPreferences.Editor editor = app_preferences.edit();
        editor.putInt("counter", ++counter);
        editor.commit(); // Very important
    }
}

main.xml中

码:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
      android:orientation="vertical"
      android:layout_width="fill_parent"
      android:layout_height="fill_parent" >

        <TextView
            android:id="@+id/text"  
            android:layout_width="fill_parent" 
            android:layout_height="wrap_content" 
            android:text="@string/hello" />
</LinearLayout>

Answer 10

如果您正在与团队中的其他开发人员一起制作大型应用程序,并且打算在没有分散代码或不同SharedPreferences实例的情况下完成所有组织,那么您可以执行以下操作:

//SharedPreferences manager class
public class SharedPrefs {

    //SharedPreferences file name
    private static String SHARED_PREFS_FILE_NAME = "my_app_shared_prefs";

    //here you can centralize all your shared prefs keys
    public static String KEY_MY_SHARED_BOOLEAN = "my_shared_boolean";
    public static String KEY_MY_SHARED_FOO = "my_shared_foo";

    //get the SharedPreferences object instance
    //create SharedPreferences file if not present


    private static SharedPreferences getPrefs(Context context) {
        return context.getSharedPreferences(SHARED_PREFS_FILE_NAME, Context.MODE_PRIVATE);
    }

    //Save Booleans
    public static void savePref(Context context, String key, boolean value) {
        getPrefs(context).edit().putBoolean(key, value).commit();       
    }

    //Get Booleans
    public static boolean getBoolean(Context context, String key) {
        return getPrefs(context).getBoolean(key, false);
    }

    //Get Booleans if not found return a predefined default value
    public static boolean getBoolean(Context context, String key, boolean defaultValue) {
        return getPrefs(context).getBoolean(key, defaultValue);
    }

    //Strings
    public static void save(Context context, String key, String value) {
        getPrefs(context).edit().putString(key, value).commit();
    }

    public static String getString(Context context, String key) {
        return getPrefs(context).getString(key, "");
    }

    public static String getString(Context context, String key, String defaultValue) {
        return getPrefs(context).getString(key, defaultValue);
    }

    //Integers
    public static void save(Context context, String key, int value) {
        getPrefs(context).edit().putInt(key, value).commit();
    }

    public static int getInt(Context context, String key) {
        return getPrefs(context).getInt(key, 0);
    }

    public static int getInt(Context context, String key, int defaultValue) {
        return getPrefs(context).getInt(key, defaultValue);
    }

    //Floats
    public static void save(Context context, String key, float value) {
        getPrefs(context).edit().putFloat(key, value).commit();
    }

    public static float getFloat(Context context, String key) {
        return getPrefs(context).getFloat(key, 0);
    }

    public static float getFloat(Context context, String key, float defaultValue) {
        return getPrefs(context).getFloat(key, defaultValue);
    }

    //Longs
    public static void save(Context context, String key, long value) {
        getPrefs(context).edit().putLong(key, value).commit();
    }

    public static long getLong(Context context, String key) {
        return getPrefs(context).getLong(key, 0);
    }

    public static long getLong(Context context, String key, long defaultValue) {
        return getPrefs(context).getLong(key, defaultValue);
    }

    //StringSets
    public static void save(Context context, String key, Set<String> value) {
        getPrefs(context).edit().putStringSet(key, value).commit();
    }

    public static Set<String> getStringSet(Context context, String key) {
        return getPrefs(context).getStringSet(key, null);
    }

    public static Set<String> getStringSet(Context context, String key, Set<String> defaultValue) {
        return getPrefs(context).getStringSet(key, defaultValue);
    }
}

在您的活动中,您可以通过这种方式保存SharedPreferences

//saving a boolean into prefs
SharedPrefs.savePref(this, SharedPrefs.KEY_MY_SHARED_BOOLEAN, booleanVar);

并且您可以通过这种方式检索您的SharedPreferences

//getting a boolean from prefs
booleanVar = SharedPrefs.getBoolean(this, SharedPrefs.KEY_MY_SHARED_BOOLEAN);

Answer 11

如何存储登录值的简单解决方案SharedPreferences.

您可以扩展MainActivity类或其他类,您将存储"您想要保留的值的值".把它放入作家和读者类:

public static final String GAME_PREFERENCES_LOGIN = "Login";

这里分别InputClass是输入和OutputClass输出类.

// This is a storage, put this in a class which you can extend or in both classes:
//(input and output)
public static final String GAME_PREFERENCES_LOGIN = "Login";

// String from the text input (can be from anywhere)
String login = inputLogin.getText().toString();

// then to add a value in InputCalss "SAVE",
SharedPreferences example = getSharedPreferences(GAME_PREFERENCES_LOGIN, 0);
Editor editor = example.edit();
editor.putString("value", login);
editor.commit();

现在你可以像其他类一样在其他地方使用它.以下是OutputClass.

SharedPreferences example = getSharedPreferences(GAME_PREFERENCES_LOGIN, 0);
String userString = example.getString("value", "defValue");

// the following will print it out in console
Logger.getLogger("Name of a OutputClass".class.getName()).log(Level.INFO, userString);

Answer 12

存储在SharedPreferences中

SharedPreferences preferences = getSharedPreferences("temp", getApplicationContext().MODE_PRIVATE);
Editor editor = preferences.edit();
editor.putString("name", name);
editor.commit();

获取SharedPreferences

SharedPreferences preferences=getSharedPreferences("temp", getApplicationContext().MODE_PRIVATE);
String name=preferences.getString("name",null);

注意:"temp"是sharedpreferences名称,"name"是输入值.如果值没有退出则返回null

Answer 13

编辑

SharedPreferences pref = getSharedPreferences("YourPref", MODE_PRIVATE);
SharedPreferences.Editor editor = pref.edit();
editor.putString("yourValue", value);
editor.commit();

读

SharedPreferences pref = getSharedPreferences("YourPref", MODE_PRIVATE);
value= pref.getString("yourValue", "");

Answer 14

editor.putString("text", mSaved.getText().toString());

在这里,mSaved可以是任何TextView或EditText从这里我们可以提取字符串.你可以简单地指定一个字符串.这里的文本将是保存从mSaved(TextView或EditText)获得的值的键.

SharedPreferences prefs = this.getSharedPreferences("com.example.app", Context.MODE_PRIVATE);

此外,无需使用包名称保存首选项文件,即"com.example.app".您可以提及自己的首选名称.希望这可以帮助 !

Answer 15

SharedPreferences的基本思想是将事物存储在XML文件中.

1. 声明您的xml文件路径.(如果您没有此文件,Android将创建它.如果您有此文件,Android将访问它.)

   SharedPreferences prefs = this.getSharedPreferences("com.example.app", Context.MODE_PRIVATE);
   

2. 将值写入共享首选项

   prefs.edit().putLong("preference_file_key", 1010101).apply();
   

   这preference_file_key是共享首选项文件的名称.这1010101是您需要存储的价值.

   apply()最后是保存更改.如果您收到错误apply(),请将其更改为commit().所以这个替代句子是

   prefs.edit().putLong("preference_file_key", 1010101).commit();
   

3. 从共享首选项中读取

   SharedPreferences sp = this.getSharedPreferences("com.example.app", Context.MODE_PRIVATE);
   long lsp = sp.getLong("preference_file_key", -1);
   

   lsp会-1如果preference_file_key没有价值.如果'preference_file_key'有值,它将返回this的值.

整个编写代码是

    SharedPreferences prefs = this.getSharedPreferences("com.example.app", Context.MODE_PRIVATE);    // Declare xml file
    prefs.edit().putLong("preference_file_key", 1010101).apply();    // Write the value to key.

阅读代码是

    SharedPreferences sf = this.getSharedPreferences("com.example.app", Context.MODE_PRIVATE);    // Declare xml file
    long lsp = sp.getLong("preference_file_key", -1);    // Read the key and store in lsp

Answer 16

您可以使用此方法保存值:

public void savePreferencesForReasonCode(Context context,
    String key, String value) {
    SharedPreferences sharedPreferences = PreferenceManager
    .getDefaultSharedPreferences(context);
    SharedPreferences.Editor editor = sharedPreferences.edit();
    editor.putString(key, value);
    editor.commit();
    }

使用此方法,您可以从SharedPreferences获取值:

public String getPreferences(Context context, String prefKey) {
  SharedPreferences sharedPreferences = PreferenceManager
 .getDefaultSharedPreferences(context);
 return sharedPreferences.getString(prefKey, "");
}

这prefKey是您用于保存特定值的密钥.谢谢.

Answer 17

保存

PreferenceManager.getDefaultSharedPreferences(this).edit().putString("VarName","your value").apply();

检索：

String name = PreferenceManager.getDefaultSharedPreferences(this).getString("VarName","defaultValue");

默认值为：如果此首选项不存在，则返回的值。

在某些情况下，您可以使用getActivity()或getApplicationContext()更改“ this ”

Answer 18

人们建议如何使用SharedPreferences有很多方法.我在这里做了一个演示项目.示例中的关键点是使用ApplicationContext和单个sharedpreferences对象.这演示了如何使用具有以下功能的SharedPreferences: -

• 使用singelton类访问/更新SharedPreferences
• 无需为读/写SharedPreferences总是传递上下文
• 它使用apply()而不是commit()
• apply()是异步保存,不返回任何内容,它首先更新内存中的值,然后异步地将更改写入磁盘.
• commit()是同步保存,它根据结果返回true/false.更改将同步写入磁盘
• 适用于android 2.3+版本

用法示例如下: -

MyAppPreference.getInstance().setSampleStringKey("some_value");
String value= MyAppPreference.getInstance().getSampleStringKey();

获取源代码在这里 和详细的API,可以发现这里的developer.android.com

Answer 19

最好的做法

创建使用PreferenceManager命名的接口:

// Interface to save values in shared preferences and also for retrieve values from shared preferences
public interface PreferenceManager {

    SharedPreferences getPreferences();
    Editor editPreferences();

    void setString(String key, String value);
    String getString(String key);

    void setBoolean(String key, boolean value);
    boolean getBoolean(String key);

    void setInteger(String key, int value);
    int getInteger(String key);

    void setFloat(String key, float value);
    float getFloat(String key);

}

如何使用Activity/Fragment:

public class HomeActivity extends AppCompatActivity implements PreferenceManager{

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout_activity_home);
    }

    @Override
    public SharedPreferences getPreferences(){
        return getSharedPreferences("SP_TITLE", Context.MODE_PRIVATE);
    }

    @Override
    public SharedPreferences.Editor editPreferences(){
        return getPreferences().edit();
    }

    @Override
    public void setString(String key, String value) {
        editPreferences().putString(key, value).commit();
    }

    @Override
    public String getString(String key) {
        return getPreferences().getString(key, "");
    }

    @Override
    public void setBoolean(String key, boolean value) {
        editPreferences().putBoolean(key, value).commit();
    }

    @Override
    public boolean getBoolean(String key) {
        return  getPreferences().getBoolean(key, false);
    }

    @Override
    public void setInteger(String key, int value) {
        editPreferences().putInt(key, value).commit();
    }

    @Override
    public int getInteger(String key) {
        return getPreferences().getInt(key, 0);
    }

    @Override
    public void setFloat(String key, float value) {
        editPreferences().putFloat(key, value).commit();
    }

    @Override
    public float getFloat(String key) {
        return getPreferences().getFloat(key, 0);
    }
}

注意:将您的SharedPreference密钥替换为SP_TITLE.

例子:

在shareperence中存储字符串:

setString("my_key", "my_value");

从shareperence 获取字符串:

String strValue = getString("my_key");

希望这会帮助你.

Answer 20

要将值存储在共享首选项中：

SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
SharedPreferences.Editor editor = sp.edit();
editor.putString("Name","Jayesh");
editor.commit();

要从共享的首选项中检索值：

SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(this);
String name = sp.getString("Name", ""); // Second parameter is the default value.